SLIP-RESISTANT, SELF ILLUMINATED FRONT LIT ARTICLE
Light transmissive non-slip treads coupled to a light directing film having a structured surface for redirecting light oriented on a first axis. The non-slip treads may appear to be specifically illuminated, as if by dedicated light fixtures, but may instead be illuminated by ordinary ambient light.
Slip resistant tapes and treads are frequently placed on slip-prone surfaces, in order to improve safety and reduce the incidence of slip and fall-type accidents. Slip resistant tapes and treads typically include adhesive-backed tapes or sheets, with a rough mineral-based or textured polymer upper surface. They may be placed, for example, on stair treads or wet areas, to decrease the incidence of a person slipping. As such, they can have an important role in residential and workplace safety. One such anti-slip product line is sold by 3M Company of St. Paul, Minn., under the Safety-Walk label. The products sold under the label feature several options of adhesive-backed anti-slip sheeting, including opaque and semi-clear, as well as different roughnesses, including fine, medium, and course.
SUMMARYSlip resistant tapes and treads are coupled with front-lit, ambient light illuminated sheeting. In some locations, this combination results in higher visual conspicuity for the tread. Particularly, in normal lighting conditions, without any lights dedicated to the tread, the tread may appear to be lit, as if by one or more dedicated and focused front lights. This improved visual conspicuity may be particularly well suited for applications where it is helpful for a person to notice that a non-slip tread has been placed in a particular area. A graphics layer may also be present, allowing the slip resistant tread to convey a message to persons in the area (for example, “DANGER” or “CAUTION” and/or commercial advertising content).
The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, explain the advantages and principles of the invention. In the drawings,
It has been discovered that combining front lit, “self-illuminated” sheeting with slip resistant adhesive-backed sheeting may provide for greater visual saliency of the slip resistant sheeting, thus improving the chance a person will notice it, and thereby potentially improving overall safety of the person, by reducing the chance of slip and fall-type accidents.
Coupled to slip resistant layer 230 is ambient light illuminated layer 220. Ambient light illuminated layer 220 is described below, but generally includes, from top to bottom, a graphic layer, a light turning film comprising an array of light directing features, and a reflector. Other intervening layers could also be included. The bottom surface of ambient light illuminated layer 220 interfaces with adhesive layer 215, which would then in turn couples to an installation surface, such as a stair tread, concrete floor, etc. Stack 233 may be provided on a release liner (not shown in
A side sectional view of ambient light illuminated layer 220 is shown in
Turning film 52 can be implemented with a sawtooth prism film, for example, or other types of light redirecting films having a structured surface for redirecting light. For example, a linear Fresnel film can be used instead of a sawtooth prism film. Alternatively, a linear microsctructure with the non-sawtooth, “roof-like” prism angles may instead be used as the structured surface. Reflector 54 can be implemented with a specular reflector, for example the Enhanced Specular Reflector (ESR) film from 3M Company. In some cases the specular reflector may have regular or irregular structures so as to provide a controlled amount of angular spreading. Specular reflectors with structure include, for example, metalized microstructured films. In some cases the reflector can be semi-specular in nature where the reflector provides a small amount of spreading or limited amount of diffusion for light incident on the reflector. Semi-specular reflectors include, for example, a lightly diffuse coating on ESR film. The optional air gap 59 can help prevent damage to the prisms of turning film 52. The air gap also provides a refractive index difference. The edges of the construction may be sealed to prevent ingress of moisture or contaminants into the air gap. The sealing technique may be to use a tape, or an adhesive or even melting the layers together. Instead of an air gap, a material with a refractive index significantly different than the refractive index of the adjacent film layers may be used thereby producing an ambient light illuminated layer that does not have an air gap and hence may be more durable.
An optional diffusing film may be placed on top of graphic 60. Additionally, or taking the place of such a diffusing film, the light transmissive slip resistant layer 230 may act as a diffuser in certain embodiments.
In use, the light directing features (for example sawtooth prisms) in turning film 52 direct light from light source 66, such as a room light, to graphic 60 in order to passively illuminate the signage for a viewer 61. Ambient light illuminated layer 220, and others similar embodiments, are described in greater detail in association with FIG. 4 of U.S. Pat. No. 8,915,002 “Self Illuminated Signage for Printed Graphics”; US Pat. Application Publication No. 2014/525,882 “Self Illuminated Shaped and Two-sided Signage for Printed Graphics”; and US Pat. Application Publication No. 2015/068080 “Self Illuminated Signage for Printed Graphics”, each of which is incorporated by reference in its entirety herein. Methods for modifying the orientation of the turning film so as to achieve a good “ambient lighting” effect at install are further described in patent application No. 62/171,413.
The entire upper surface of sheet 240, sheet 260, etc. may comprise a light transmissive slip resistant layer, as described earlier, or striped portions may alternate between light transmissive slip resistant portions and opaque slip resistant portions. Of course, it is not necessary to have portions of ambient light illuminated layer underneath the opaque sections of the sheet which can provide additional adhesion area thereby improving the toughness and abrasion resistance of the signage.
Ambient light illuminated slip resistant sheets with graphics were produced and luminance values measured. These examples are merely for illustrative purposes only and are not meant to be limiting on the scope of the appended claims
Test Methods—Luminance MeasurementSamples were placed on the floor in a 10 foot tall room lit with ceiling mounted, fluorescent artificial light. Luminance measurements were made using a Minolta Luminance Meter LS-100 (available from Konica Minolta Sensing Singapore Pte Ltd). Luminance values are expressed in units of cd/m2 (nits) and recorded in Table 1. Gain for the Examples 1 through 4 was calculated by dividing the luminance value of the Example by the luminance value of Comparative Example 1 and the results were recorded in Table 1.
All samples were printed using a Roland SP-300i eco-solvent printer (available from Roland USA).
Comparative Example 1—Sample Construction White Vinyl SignA white vinyl sample 50.8 micron thick (white vinyl film #180C-151-010 available from 3M Company, St. Paul, Minn.) was printed using a Roland SP-300i printer. The printed pattern was a typical floor safety warning pattern with diagonal yellow and black stripes with an area of approximately 5×21 inches. The luminance of the yellow regions was used as the reference luminance for comparing the luminance of the various constructions noted below.
Example 1—Sample Construction Bright SAFETY WALKThe bright SAFETY WALK demonstration was constructed using, in sequence from closest to the viewer to the floor, an oversized 620B SAFETY WALK layer, 3M ENVISION Matte 8550 Overlaminate (both available from 3M Company, St. Paul, Minn.), a 2 mil spacer layer of PET and an ambient light illuminated layer.
The oversized 620B SAFETY WALK material was cut roughly ½″ per edge larger than the printed sign dimensions. This extra width adhered the final sign the floor surface.
The 8550 overlaminate was printed on the non-adhesive side using a Roland SP300i printer. The print side was dried and then adhered to the SAFETY WALK adhesive, thereby protecting the printed image which was sandwiched in the SAFETY WALK adhesive.
The 2 mil layer of PET was adhered to the 8550 adhesive layer to ensure an airgap between the 8550 and the ambient light illuminated layer turning film.
The ambient light illuminated layer comprised sawtooth shaped features oriented as described in U.S. Pat. No. 8,915,002 “Self Illuminated Signage for Printed Graphics,” and as is seen in
The sign was then sealed to the floor by cleaning the floor with isopropyl alcohol to remove wax and then adhering the edges of the oversized SAFETY WALK material to the floor.
Yellow areas of the resulting construction were measured with the Minolta camera with the Bright SAFETY WALK sign located directly under an overhead fluorescent light in a comparable position to Comparative Example 1. Results are recorded in Table 1.
Example 2—Sample Construction Bright BorderThe Bright Border SAFETY WALK demonstration was constructed using, in sequence from closest to the viewer to the floor, an undersized 620B SAFETY WALK layer, an oversized 3M ENVISION Matte 8550 Overlaminate, both available from 3M Company, St. Paul, Minn.), a 2 mil spacer layer of undersized PET and an ambient light illuminated layer.
The undersized 620B SAFETY WALK material was cut roughly ½″ per edge smaller than the printed sign and ambient light illuminated layer dimensions. The oversized 8550 overlaminate was printed on the non-adhesive side using a Roland SP300i printer. The print side was dried and then centered on and adhered to the SAFETY WALK adhesive, thereby partially protecting the printed image which was sandwiched in the SAFETY WALK adhesive. The 2 mil layer of undersized PET was adhered to the center of the 8550 adhesive layer to ensure an airgap between the 8550 and the ambient light illuminated layer turning film but provide an adhesive layer from the 8550 around the edges of the film stack.
The ambient light illuminated layer comprised sawtooth shaped features oriented as described in U.S. Pat. No. 8,915,002 “Self Illuminated Signage for Printed Graphics” and as is seen in
The sign was then sealed to the floor by cleaning the floor with isopropyl alcohol to remove wax and then adhering the edges of the oversized 8550 overlaminate to the floor. Yellow areas of the resulting construction were measured with the Minolta camera with the Bright Border sign was located directly under an overhead fluorescent light in a comparable position to Comparative Example 1. Results are recorded in Table 1.
Example 3—Sample Construction Patterned SAFETY WALKThe Patterned SAFETY WALK demonstration was constructed using, in sequence from closest to the viewer to the floor, stripes of 620B SAFETY WALK, a 3M ENVISION Matte 8550 Overlaminate layer (both available from 3M Company, St. Paul, Minn.), a 2 mil spacer layer of PET and an ambient light illuminated layer.
The 620B SAFETY WALK material was cut into diagonal stripes the same shape and size as the printed black portion of the diagonal yellow and black striped pattern. The strips of SAFETY WALK material were then adhered only to the printed black regions of the diagonal yellow and black striped pattern. The oversized 8550 overlaminate was printed on the non-adhesive side using a Roland SP300i printer leaving a clear border of nominally ½″ on all edges of the printed area. The print side was dried and then centered on and adhered to the SAFETY WALK adhesive with the SAFETY WALK strips aligned to the black stripes on the printed pattern. The 2 mil layer of PET was adhered to the center of the 8550 adhesive layer to ensure an airgap between the 8550 and the ambient light illuminated layer turning film but provide an adhesive layer from the 8550 around the edges of the film stack.
The ambient light illuminated layer comprised sawtooth shaped features oriented as described in U.S. Pat. No. 8,915,002 “Self Illuminated Signage for Printed Graphics” as per
The Multiple Direction SAFETY WALK demonstration was constructed as the Bright Border sample construction except the underlying ambient light illuminated layer was cut into two pieces and ½ was rotated 180 degrees. In this fashion, half the sign was bright for viewers approaching from one direction and half the sign was bright for viewers approaching from the opposite direction.
Yellow areas of the resulting construction were measured with the Minolta camera with the Multiple Direction SAFETY WALK sign was located directly under an overhead fluorescent light in a comparable position to Comparative Example 1. Results are recorded in Table 1.
Measurement DataThe signs noted above were fabricated and the luminance measured on the yellow portion of all signs. The relative gain was calculated by dividing by the IJ180 yellow reference value (Comparative Example 1).
Claims
1. A slip-resistant, self-illuminated front lit adhesive backed article comprising:
- a light transmissive friction layer, comprising an upper and lower major surfaces, wherein the upper major surface comprises a rough surface having static coefficient of friction of at least 0.50; and,
- an ambient light illuminated layer having an upper major surface and a lower major surface comprising layers in the following order from upper to lower: a graphic layer comprising a printed graphic; a turning film layer having a first structured surface for redirecting light, and a second surface opposite the first surface, the first structured surface comprising a plurality of elongated, sawtooth shaped light directing features; and a reflective layer comprising a reflector.
2. The article of claim 1, further comprising:
- additional layers between the light transmissive friction layer and the ambient light illuminated layer.
3. The article of claim 1, further comprising:
- additional layers between the layers that comprise the ambient light illuminated layer.
4. The article of claim 1, further comprising:
- an air gap layer between the light transmissive friction layer and the ambient light illuminated layer.
5. The article of claim 1, wherein the lower major surface of the light transmissive friction layer is adhesively coupled to the upper major surface of the ambient light illuminated layer.
6. The article of claim 5, wherein the upper major surface has a static coefficient of friction of at least 0.60.
7. The article of claim 5, further comprising:
- an adhesive layer having an upper and lower major surface, the upper major surface coupled to the lower major surface of the ambient light illuminated layer.
8. The article of claim 7, further comprising:
- an release liner having an upper and lower major surfaces, the upper major surface comprising a silicone-based release layer, the upper major surface adhesively coupled to the lower major surface of the adhesive layer.
9. The article of claim 1, wherein the rough surface comprises a plurality of light transmissive particles having an average particle diameter of at least 500 μm.
10. The article of claim 9, wherein the rough surface comprises a plurality of light transmissive particles having an average particle diameter of at least 600 μm.
11. The article of claim 10, wherein the rough surface comprises a plurality of light transmissive particle having an average particle diameter of at least 700 μm.
12. The article of claim 1, wherein the turning film has an orientation, which is orthogonal to the direction of the sawtooth shaped light directing features.
13. The article of claim 1, wherein the graphic layer comprises photoluminescent material.
14. The article of claim 1, wherein the light-transmissive friction layer comprises an index-matching material applied to the upper major surface.
15. The article of claim 14, wherein the index-matching material comprises a UV cured acrylate resin.
16. The article of claim 1, wherein the article comprises a sheet.
17. The article of claim 1, wherein the article comprises a roll.
18. The article of claim 1, wherein the light transmissive friction layer has static coefficient of friction of at least 0.60.
Type: Application
Filed: Sep 30, 2016
Publication Date: Oct 11, 2018
Inventors: John C. Schultz (Afton, MN), Erik A. Aho (New Richmond, WI), John E. Gozum (Stillwater, MN), Michael J. Sykora (New Richmond, WI)
Application Number: 15/765,335